Catalytic conversion of hydrocarbons



Sept. 7, 1943- w. L BENEDlc'r CATALYTIC CONVERSION OF HYDROCARBONS FiledJan. a, 1940 short.

d Patented Sept. 7,-'1943 UNITE-o STATESL PATENT oFFlcE CATALYTICCONVERSION OF HYDRO CARBONS Wayne L. Benedict, Chicago, Ill., assignerto Universal Oil Products Company, Chicago, Ill., a corporation ofDelaware Application January s, 1940, serial No. 312,854

(ci. '19e- 52) 9 Claims.

This invention relates to a process for converting hydrocarbon oil intosubstantial yields of desirable products including gasoline suitable foruse in aviation motor fuel. More particularly, it concerns a process forcatalytically cracking hydrocarbon oil and converting the 'resultantgasoline into `substantial yields of high antiknock gasoline which isrelatively vfree of olefin hydrocarbons.

The use of various catalytic agents -to assist the thermal conversion ofhydrocarbon oil to motor fuel has been practiced. Among the catalystsproposed are the reduced metal catalysts including iron, cobalt, etc.,which are subject to a number of Vdisadvantages including the fact thatthey are poisoned by sulfur compounds which may be present in the oilsundergoing conversion and furthermore that they tend to promote gas andcarbon-forming reactions with the net result that the catalyst life iscomparatively Another type of cracking catalyst is the activated earthtype in which naturally-occurring clays are treatedwith acids or otherchemicals to increase their catalytic activity.

Still another type of catalyst is made up of activated aluminaorfmagnesia whichmay have deposited thereon various promoting oxidesfrom the left-hand column of the 4th, 5th and 6th Y l groups of theperiodic table and include particularly such oxides as those ofchromium; molybdenum, vanadium, etc. A

A further type ofJ catalyst, which is the preferred material of thisinvention, is the so-called silica-alumina, silica-zirconia, andsilica-alumina-zirconia composite which ismanufactured briquettes, etc.,or inthe form of `finely divided powders which are carried in suspensionin a stream of liquid or vaporized hydrocarbon.l The temperatures underwhich the catalysts have been used range from approximately 500-1200 F.and

Vpressures from substantially atmospheric -to 1000 In one specificembodiment the present invention comprises a process for convertinghydrocarbon oil into substantial yields of gasoline suitable for use inaviation motorvfuel which comprises contacting said hydrocarbon oil withparticl'es of cracking catalyst contained in a reactor at a temperatureof approximately 9001200 F, and a pressure substantially atmospheric,fractionating the reaction products into gas, gasoline, an intermediateboiling fraction and insufficiently converted oil, removing the gas andthe intermediate boiling fraction, mixing the gasoline and theinsufficiently converted oil, contacting the mixture with a powderedcracking catalyst at a temperature of approximately 500-900 F. and apressure of -1000 pounds per square inch, fractionating the reactionproducts into substantially olen-free gasoline and insufficientlyconverted oil containing the catalyst in suspension, mixing thesuspension with the original hydrocarbon oil, heating the mixture to atemperature within the range of 900-1200" F., passing the heated mixtureto a flashing Zone, removing a residual portion containing catalyst insuspension, and passingL the vaporous portion to contact with saidcatalyst particles as previously mentioned.

One embodiment of the present invention is illustrated in theaccompanying drawing, which is purelydiagrammatic and should not beconstrued as` limiting the process to the exact apparatus or flow shown.No attemptihas been made is introduced through line l, valve 2, line3,`valve 4, pump 5, valve 6 to coil 1 which'is disposed in heater B. Theheated oil passes through line 9 and valve I0 to flash chamber Il. Aresidual portion is withdrawn through line I2 and valve I3. The vaporousportion is removed through line I4 and valve i5 to catalytic reactor 16.The

reactor may comprise manifolded tubes or a chamber containing catalystparticles disposed therein. The reactor may be supplied in duplicate .inorder to permit a continuous process wherein one reactor is in theprocess phase and the other reactor in the reactivation phase of a'equipped so that additional heat may be introduced into the system asfor example in the`case of tubes which may be disposed in a heatedzone.l

The temperature at which the reaction is car- `rieti out :ls within therange of approximately complete cycle. The catalyst container may be` IlPoint.

tained at a pressure in excess of that employed `900-1200 F. and apressure of substantially atmospheric or slightly superatmospheric, sayof the order of 50-150 pounds per square inch. The reaction productspass through line I1, valve I8 to fractionator I9. Process gasescontaining poylmerizable olefin hydrocarbons are removed through line 20and valve `2I. An intermediate boiling fraction which has an initialboiling point as a rule in excess of 300 F. and may comprise a naphthafraction suitable for blending with automobile motor fuel or maycomprise a furnace distillate or tractor fuel, is removed through line,22 and Valve 23. A suitable gasoline fraction, for example, of about300 F. end-point, may be removed through line 24, cooler 25, valve 26,line 2-1, pump 28, valve 29 to coil 30 which is disposed in heater 3I.Insufficiently converted oil is removed from fractionator I9 throughline 32 and valve 33 joining with line 21 and being mingled therein withthe gasoline from line 24. The mix- `ture is heated to a temperaturewithin the range of 50G-900 F. and asuperatmospheric pressure of 50-1000pounds per square-inch and suitably of the order of 200-400 pounds persquare inch, and is passed through line 34 and valve 35 to catalyticreaction zone 36. A powdered catalyst which may be the same or differentfrom 'that used in reactor I6, but which is in finely divided form, isintroduced from the catalyst charger 31 through line 38, valve 39,coil'40 whichi's disposed in heater 4I, and through line 42 and valve 43which joinswith line 34. The catalyst may be suspended in a portion ofthe charging stockvor more suitably in an intermediate boiling 4fractionwhich is relativelyy refractory to catalytic cracking. The reactionproducts from the reaction zone, which is any suitable type of reactorincluding a coil disposed in a furnace or a tower containing suitablecontacting members, pass through line 44, valve 45 to fractionator 46.Gasoline which is substantially olefin-free is removed through line 41and valve 48. Insumciently converted oil containing catalyst insuspension is passed through line 49 and valve 50 to line 3 and isreturnedthence by previously described routes to flash chamber II. Thespent catalyst suspended in residual oil is removed through line I2 andvalve I3 to a suitable separation step not shown, and may be recoveredand excess of 900 F., reactivation with an oxygencontaining gas, whichis necessary at regular intervals, can be carried out with no delay inheating the catalyst to a temperature at which combustion can bestarted. On the lother hand, when using a. cracking catalyst in therelatively low temperature ranges of 50G-900 F., some means of heatingthe catalyst to a temperature in excess of 900 F. must be resorted toafter the processing step has been completed and before the reactivationstep is begun. This occasions considerable A delay and moreover oftenresults in considerable liquid volume losses of the hydrocarbon oilcharged due to the fact that a portion of the oil is retained byadsorption on the catalyst particles.I Furthermore, after reactivationis complete, it is necessary to cool the catalyst bed from the higherlevel of reactivation to the lower level of processing in order to avoidundesired reactions which-occur in the higher temperature range. Thisalso occasions considerable delay since the peak temperature ofreactivation is ordinarily of the order of 1300-1500 F.

When employing a powdered catalyst under the low temperature conditions,however, various means of recovering the residual oil may be employed,such as washing the catalyst with a lowboiling solvent, treating themixture with water containing a wetting agent whereby the catalystseparates substantially free of oil, etc. The reactivation can becarried out under any desired conditions at the convenience of theoperator and after being cooled, .the catalyst is returned to thesystem. 'Ihe reactivation step thus entails a minimum loss ofhydrocarbon oil and n'o loss in time in the processing step. Itfurthermore makes unnecessary the use of additional reactors which mustbe provided where fixed beds of catalyst are used in order to compensatefor the added time of heating, reactivating and cooling.

A further advantages ilies in the fact that the partially spent catalystis contacted with the incoming oil and effects a considerable amount ofY tor and the use of a different catalyst which may be more desirablefor use in the powdered catalyst reactor.

'The following example is given to illustrate the usefulness andpracticability ,of the process, but

ture fromfheater 8 at a point near the bottom of the flash chamber. Thetemperature maintained in the flash chamber is somewhat in excess ofthat to be used in reactor I6 so that a considerable amount of reactiontakes place at this Moreover the ash chamber is mainin reactor I6 inorder to maintain a part of the oil in the liquid form. The exactconditions of temperature and pressure used at this point will dependentirely upon the character of the charging stock and of the residualoil which it is desired to make. A portion or all of thefractionatorbottoms containing spent catalyst infsuspension may bewithdrawn through line 5I and valve should not be construed as limitingit to the exact conditions given therein.

When processing'a Midcontinent topped crude oil in the manner describedusing a silica-alumina-zirconia catalyst, the catalyst in reactor I 6may be used in the form of la" diameter spheres at a processingtemperature of 930 F. and pressure of approximately 30 pounds per squareinch.

' 'Ihe gas may be removed from the fractionator inch, has an octanenumber of approximately 77,

and a bro'mne number of about 2. The residual oil containing thecatalyst in suspension may be mixed with the topped crude oil and heatedto a temperature of 1000 F., passed to ash chamber Il which ismaintained at about 950 F. and a pressure of 200 pounds per square inch.A residual oil containing spent catalyst in solution may be continuouslywithdrawn and a vaporous portion passed therefrom into reactor i6 asdescribed. A total yield of approximately 50% of 300 F. end pointgasoline may be obtained together with 18% of tractor fuel and 10% ofgasoline from the polymerizable olens in the gases. The residue may beused as fuel oil.

I claim as my invention:

1. A process for converting hydrocarbon oil into substantial yields ofvaluable products including high antiknock gasoline which comprisescontacting said hydrocarbon oil in vaporous form with a granularcracking catalyst under catalytic cracking conditions of temperatureandpressure, iractionating the reaction products into gas, gasoline andinsufficiently converted oil, mixing a portion of said gasoline and saidinsuiiiciently converted oi1,-heatingrthe mixture to a temperature ofapproximately 500-900 F., mixing therewith a heated powdered catalyticagent, treating the mixture in a reaction zone under condi- 'tions oftemperature and pressure adequate to eiect substantial conversionthereof into substantially olefin-free gasoline, fractionating thereaction products into gas, gasoline, and insufficiently converted oilcontaining said catalytic agent in suspenslomvcombining said.insufficiently converted oil with said hydrocarbon oil, heating themixture to a temperature within the range of 900-1200 F., passing theheated mixture to a flashing zone, removing a residual oil containingspent catalyst in suspension, and supplying the vaporous portion tocontact with said granular cracking catalyst.

2. A process for converting vhydrocarbon oil into substantial yields ofvaluable products in' cluding substantially olefin-free gasoline whichcomprises mixing said hydrocarbon oil with an insumciently converted oiland partially spent powdered catalystl produced as hereinafterdescribed, heating the mixture to a temperature within a range ofapproximately 900-1200 F., passing the heated mixture to a hashing zoneat reduced pressure, removing therefrom a residual portion containingspent catalyst in suspension, passing the vaporous portion to primarycatalytic cracking step, therein contacting said vapors with particlesof cracking catalyst at a temperature and pressure adequate to effectsubstantial conversion thereof into olefin-containing gasoline,fractionating the reaction products into gas, gasoline, and insuicientlyconverted sure, removing therefrom a residual oil containing saidcatalyst in suspension, passing a vaporous fraction to a primarycatalytic cracking( step, contacting the vapors with formed particles ofcracking catalyst under conditions of temperature and pressure `adequateto eiect substantial conversion into olefn-contining gasoline,fractionating the reaction products into gas, gasoline, an intermediateboiling fraction and insufiiciently converted oil, removing saidintermediate boiling fraction, mixing said gasoline and saidinsufficiently converted oil, heating the mixture to a temperaturewithin the range of approximately G-900 F., mixing therewith a powderedcracking catalyst, passing the mixture -to a secondary cracking stepunder conditions of temperature and pressure adequate to produce asubstantially olefin-free gasoline, fractionating the reaction productsinto gas, gasoline and insuciently converted oil containing partiallyspent catalyst in suspension, and combining the suspension with saidhydrocarbon oil as previously described.'

4. A process for converting hydrocarbon oil into substantial yields ofvaluable products including high antiknock gasoline which comprisesmixing said hydrocarbon oil with an insuiiciently converted oilcontaining catalyst in suspension produced as Ihereinafter described,-heating the mixture to a temperature within the range of 9001200-F. anda pressure of approximately 100-1000 pounds per square inch, passing themixture to a flashing zone maintained at a ternperature in excess of 900F., maintaining'a-liquid level of residual oil containing catalyst insuspension in said flashing zone, continuously withdrawing a portion ofsaid residual oil, pass-v ing the vapors from the flashing zone to apri-- mary cracking step at a temperature in the range of approximately900-1200 F., contacting the vapors with preformed particles of crackingcatalyst, fractionating the reaction products into gas, gasoline andinsuiliciently converted oil,

oil, combining a portion ofsaid gasoline with said insulcientlyconverted oil, heating .the mixture to a temperature within the range ofSOO-90.0 F. and under a pressure of 50-1000 pounds per square inch,mixing therewith a powdered catalytic composite, treating themixtureu'nderconditions of temperature and pressure adequate to effectsubstantial conversion thereof into substantially olen-free gasoline,fractionating the reaction products into-gas, gasoline and insufcientlyconverted oil containing said catalyst in suspension and combining saidinsufllciently converted oil and said catalyst with said hydrocarbon oilas previously described.

`3. A process for'converting hydrocarbon oil into substantial yieldsofvaluable products including gas and gasoline which comprises' mixingsaid hydrocarbon oil with a suspension of mixing a portion of saidgasoline with said in` suilciently converted oil, adding thereto apowdered catalyst and passing the mixture to a secondary cracking stepat a temperature within the range of 50G-900 F. and a pressure ofl50-1000'pounds per square inch, fractionating the reaction productsinto gasoline, gas and insuiciently converted oil containing partiallyspent catalyst in suspension, and mixing the suspension with saidhydrocarbon oil as previously described. Y

5. The process for-converting hydrocarbon oil into substantial' yieldsof valuable products including high antiknock gasoline which comprisesmixing said hydrocarbon oil with partially spent vpowdered catalystsuspended in an insuiciently converted oil produced as hereinafterdescribed, heating the mixture to a temperature within the range of900-1200cl F., passing the heated mixture to a flashing zone. removingliquid residue containing. said catalyst in suspension, passing vaporsfrom said :dashing zone to contact with preformed cracking catalystparticles, :fractionvating the reaction products .into gas, gasoline andinsuiliciently converted oil, mixing a portion of said gasoline and saidinsuiciently converted oil, heating the mixture to a temperature withinthe rangeof 50G-900 F., mixing therewith a powdered cracking catalystselected from the group consisting of silica-alumina, silicazirconia andsilica-alumina-zirconia, passing the mixture to a reaction zone underconditions of range of 900-1200 F., to form oleflnic gasoline therefrom,fractionating the resultant products to separate gasoline fractions,insuiiciently converted products and an intermediate product, recoveringsaid intermediate product, passing at least a portion of said gasolinefractions and at least a portion of said insufficiently convertedproducts through a reaction zone in admixture by to producesubstantiallly olen-free gasoline, and recovering the last-namedgasoline.

8. A conversion process which comprises passing hydrocarbon vaporsthrough a bed of cracking catalyst at a temperature in the approximaterange of 900-1200 F. to form olenic gasoline therefrom, passinginsufficiently converted products of said cracking step and at least aportion of said oleiinic gasoline through a reaction zone in admixturewith a powdered cracking catalyst and therein subjecting the mixture toa temperature in the approximate range of 50G-900 with a powderedcracking catalyst and therein subjecting the mixture to a temperature inthe approximate range of 50G-900 F., whereby to produce substantiallyolengfree gasoline, and recovering the last-named gasoline.

'7. A conversion process which comprises passing hydrocarbon vaporsthrough a bed of cracking catalyst at a temperature in the approximaterange'of 900-l200 F. to form olenic gasoline therefrom, fractionatingthe resultant products to separate a gasoline fraction having an endboiling point of about 300 F., and intermediate product containing theheavier gasoline fracv tions, and insufliciently converted oil,recovering said intermediate product, passing the firstmentionedgasoline fraction and the insufflcient- 1y converted oil through areaction zone in admixture with a powdered cracking catalyst and thereinsubjecting the 'mixture to a temperature in the approximate range of50G-900 F., where- F., whereby to produce substantially olen-freegasoline, separating the resultant products into vapors and a suspensionof unvaporized oil and powdered catalyst, fractionating and condensingthe vapors, heating at least a portion of said suspension to atemperature in the approximate range of 90o-1200" F. and passing vaporsthus formed through said bed of catalyst.

9. A conversion process which comprises passing hydrocarbon vaporsthrough a bed of cracking catalyst at a temperature in the approximaterange of 900-1200F. to form olefnic gasoline therefromy fractionatingthe resultant products to separate a gasoline fraction having an endboiling point of about 300 F., an intermediate product containing theheavier gasoline fractions, and insuiciently converted oil, passing thefirst-mentioned gasoline` fraction andthe insuiciently converted oilthrough a reaction zone in admixture with a powdered cracking catalystand therein subjecting the mixture to a temperature in the approximaterange of G-900 F., whereby to produce substantially olen-free gasoline,separating the resultant products into vapors and a suspension ofunvaporized oil and powdered catalyst, fractionating and condensing thevapors, heating atleast a portion of said suspension to a temperature'in the approximate range of 900-1200 F. and passing vapors thus formedthrough said be`d of catalyst.

WAYNE L. BENEDICT.

